多信道S-ALOHA功率攀升机制的性能分析

针对海量机器类终端同步入网时因重传带来的功耗急剧增加问题,以第i个时隙内进行第j次随机接入的用户数 作为状态变量,给出了带功率攀升机制的多信道S-ALOHA的暂态性能分析办法(尤其是功耗与时延模型)及其接入强度稳定时的近似形式。以3GPP机器类通信两种业务模型进行数值仿真,验证了所提性能分析办法及其近似形式的正确性,给出了用户数、退避区间、最大重传次数对功率攀升机制的性能影响,提出了适当增大退避窗口以时延换取能耗的优化策略。

Analysis of the performance of the multichannel S-ALOHA by the power ramping scheme

Aiming at the problem of the rapid increase in power consumption caused by retransmission under the massive machine type devices concurrent access to the network. Therefore, in this paper, by use of the number of contending devices that transmit the j-th preamble at the i-th random access slot as the state variable, we present a transient performance analysis method (especially the power consumption and access delay model) for the multi-channel S-ALOHA by the power ramping scheme as well as a simplified form under stable access attempts. By taking two kinds of machine type communications traffic models proposed by the 3GPP as examples, numerical simulation is conducted to validate the effectiveness of the proposed performance analysis method as well as its simplified form, to analyze the effects of the number of users, the size of the back-off window, and the maximum number of retransmissions on the performance of the multi-channel S-ALOHA by the power ramping scheme, and to propose an optimization strategy for appropriately extending the back-off window to exchange power consumption with delay. These practices together can provide a good reference for performance analysis and optimization design of the random access channel under the massive machine type devices concurrent access to the netwok.